


Careful What You Wear To The Beach

by bgn846



Category: Final Fantasy XV
Genre: Fluff, Gen, Merfolk AU, Mistaken Identity, just something silly, merman, octomen
Language: English
Status: Completed
Published: 2020-06-03
Updated: 2020-06-03
Packaged: 2021-03-04 04:40:44
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,588
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24517822
Author URL: https://archiveofourown.org/users/bgn846/pseuds/bgn846
Summary: Prompto thinks his new outfit will make him look better than ever, the only problem is he looks like someone else now.
Relationships: Gladiolus Amicitia & Prompto Argentum & Noctis Lucis Caelum & Ignis Scientia
Comments: 8
Kudos: 49





	Careful What You Wear To The Beach

**Author's Note:**

> I couldn't think of anything to write for mer may until June 1st go figure. lol 
> 
> I hope you all enjoy this silly little tale about tails. 
> 
> I saw some artwork by the wonderful @mintfoxmimi [Mintfoxmimi Tumblr](https://mintfoxmimi.tumblr.com/) and her octomen recently so that's how i'm envisioning the bros in the fic.

When the doorbell rang Prompto nearly tripped over his own feet rushing to the door. Finally, the delivery truck had made it all the way out to his place. Granted, working at the lighthouse meant he was the last on the route. Ripping the old, wooden, weather battered door open he was greeted by a nonplussed UPS driver. 

The item he so desired sat hiding in a fairly good sized cardboard box. The delivery man handed the package off and with a slight head nod he had turned and gone. Left again on his own Prompto began wrestling the box through the tiny corridors of the cottage he lived in. One perk of manning the lighthouse was the privacy. Not many people came out that far and he could do as he pleased. 

This was a good thing, and bad in some regards. Prompto had a bit of an obsession and this lifestyle merely fueled it. Prompto wanted to be a merman. 

Mer folk were real. Everybody knew that, so no one thought he was truly crazy for liking the other species. It was his unbridled desire to actually be one that caught some of his friends off guard, hence his reasons for indulging in his fantasies in private. The mer really only interacted with certain humans, mostly the ones in control of the government. It wasn’t like they could come out of the water and stroll into town. 

Prompto had never actually met one, he’d only seen pictures in the news or on TV when they came ashore to discuss politics and such. However, with his new custom made treasure currently ensconced in the box he was holding, he could play the part a little better.

Sliding the box on his kitchen table Prompto ignored the stack of magazines it displaced, and began carefully opening the item. He couldn’t risk accidentally cutting it, this thing cost a small fortune. After several seconds his floor was littered with piles of crumpled paper revealing the thing he’d bought. A cacophony of iridescent greens and purples glittered in the dim lighting. Imagining what it would look in the setting sun made the blond pause in his work. Shaking his head a minute later to clear his thoughts, he ran upstairs to change. The sunset was only an hour away; he needed to get ready and go down to his private beach. 

Prompto knew the dangers of ordering things online, he really did, but the idea that he could have a realistic fish tail meant he threw caution in to the wind. Now, as he sat on the beach trying to wiggle into his new tail things were not going as planned. He’d measured himself three times before ordering to hopefully ensure the perfect size. The maker had even warned him that the fit would be snug. The description online had said it would make for a more immersive experience, whatever that meant. He was starting think they were referring to it feeling like second skin, since it was so tight. The material had some give but it was form fitting. There was only one zipper that ran from the thigh up to the waistline on the side. He was supposed to squeeze his legs up past his knees into this thing, and then zip up the rest. At times like this he wished for a helping hand.

After about twenty minutes Prompto had finally managed to get his tail on and zipped up. He had to suck in a breath to get the last few inches, but hey it was all for the look, right? Rolling over on the sand to grab his phone Prompto began setting up his shot. This tail was fantastic, it caught the sunlight beautifully and even had some glitter glued on in spots. However, the shots weren’t coming out great; Prompto realized he needed to sit partially in the water for the full effect. Scooting the ten feet to the shore line winded him; not being able to walk was really hard. 

Taking a look at the screen now showed the ocean and his tail. Okay now he was getting somewhere. Twisting slightly he tried to angle his body to look cute. No one would see these but he still wanted to look good. Slowly moving his thumb into position Prompto was hovering over the shutter button on his phone. This was going to be epic. 

Prompto wasn’t sure he’d actually taken the picture. He also wasn’t sure he was still among the living either. The world had gone suddenly dark and he couldn’t breathe. 

The not breathing part took way longer to sink in than it should have. Struggling to reach out with his arms he found no resistance. Nothing was in his reach; nothing was there to grab a hold of. Finally forcing his eyes open revealed the expanse of the ocean before him. The salt water stung but he managed to look around. Something dark and big was dragging him away! A long tendril was wrapped around his ankles preventing escape. 

Using what little energy he had left Prompto bent forward trying to reach his feet. Maybe if he got the thing loose, he’d be able to swim up for air. However, the thing wrapped around his ankles was solid muscle. Prompto was only able to poke at it and nearly broke a fingernail trying to pry it away. Oddly enough this small attempt had an effect. 

The thing dragging him abruptly stopped and turned around. Prompto almost forgot he couldn’t breathe underwater and yelled. The lack of air was already burning his lungs, and didn’t help the shock of seeing a human face staring back at him. It was a dude? The half guy looked mightily confused as Prompto tried to swim upwards. It wasn’t until he began frantically motioning with his hands towards his throat that the guy, or maybe mer grabbed him again. 

Instantly worried that he’d be drug deeper still, Prompto tried to point to the sky, but the half dude half thing was already taking him back to the surface. The moment they broke the water line Prompto began sputtering and coughing. Astrals’ he’d been so close to drowning, though he wasn’t out of the hot seat yet. 

Prompto had been so focused on taking huge lung fulls of air into his body that he’d not realized the mer was holding him up. Suddenly worried he might let go Prompto panicked. “Don’t let me go under, please!” he begged. 

The mers face displayed an interesting mix of confusion and concern. “I gotcha,” he offered after a moment. “Um – is your tail lame? Or are your gills stuck?”

All rational thought left Prompto’s brain in that moment. This mer thought he was another mer? Holy shit. “I’m human!” he blurted out in fear that he’d be taken underwater again. 

The guy narrowed his amber eyes at Prompto and frowned. “Humans have legs. Do you think I’m stupid or something?” His elongated pointy ears seemed to take a cue from his downturned lips and sagged as well. 

“It’s a fake tail! Honest! Here I’ll show you.” Prompto yelped as he tried to reach his side. The mer had been supporting Prompto’s weight by holding him under his arms. Flailing around helplessly Prompto realized he couldn’t reach the zipper. “I’m human, please believe me,” He whimpered.

“Maybe,” he grumbled.

Prompto couldn’t think of anything else to say, he was exhausted and a good ways from the shoreline. The lighthouse was still visible in the distance, but if this mer let him go he’d probably sink again and die. “Please don’t hurt me.” He ventured pathetically.

“Huh?! I’m not gonna hurt you, I was trying to save you!” The mer squawked.

“By dragging me underwater?!” 

“I thought you were beached.”

“You could have asked me!” Prompto wailed. 

This time the mer looked away sheepishly and sighed. “I was just teasing, monofins are fun to pick on sometimes.”

Prompto wracked his brain for what the mer might have been talking about. What the hell was a monofin? His expression must have tipped the mer off and he continued explaining. 

“Ya know like you, just one tail.” He offered like it made total sense. 

“What are you?” Prompto asked now suddenly worried that this mer wasn’t actually a mer.

“I’m an octoman why?”

Octoman sorta made sense, the thing that had been wrapped around his ankle had looked like a tentacle. He’d never paid much attention to the other sub species of mer, his main focus had been the ones with shiny pretty tails. Now as Prompto floated in this octoman’s arms, he kicked himself for his lack of education on the subject. 

With this new tidbit of information a thousand and one questions flooded his brain. However, before he could ask any of them something nearby caught his attention. Another head was sticking out of the water and it was looking right at him. Shouting out of surprise he tried to push back. The octomans grip was strong and didn’t waver. 

“Calm down there buddy, you’re safe.”

“What’d you find Gladio?” The other mer asked as he floated closer. “Picking on monofins again, Iggy won’t like that. His cousin married one, remember.”

“Yeah I know, Noct! I thought he was beached. Besides he’s human, or so he claims.” This mer, Gladio offered with a pout. 

A puff of air signaled the arrival of yet another party. He seemed unfazed by the sight and circled them a few times. His piercing greens eyes never leaving Prompto’s face. Finally the mer edged close enough that Prompto could see his beauty marks. Taking a small breath, Prompto tried working out what he could say next. When several strong tentacles began wrapping around his chest he panicked again. “Don’t drag me under!”

“He’s checking you out, calm down.” Gladio announced as the mer disappeared under the water line. “I won’t let you go under, trust me.”

Prompto tried to relax but it was so hard. This other mer with green eyes, Iggy maybe, was pinching his sides and poking his tail. He could feel the mer testing the flexibility by moving his legs at the knee joint. After a minute the mer surfaced again and looked confused. 

“Humans can’t breathe underwater so why would you wish to come into the sea.” 

“That wasn’t my plan! I was trying to take a picture on the beach with my new tail and then um – Gla—Gladio grabbed me.” Prompto huffed dramatically. 

Iggy shook his head and glared at Gladio. “I’ve warned you about this, but do you listen!”

“His tail was pretty; I wanted to see it better.” Gladio defended. 

“Ruffian.” Ignis groaned. 

“Can you help me get back, I don’t know how to swim with this thing on.” 

The dark haired mer laughed at the comment and grinned. “See I told you that monofins are slower. No one believes me but it’s true.”

“Enough, come the sun is setting and humans don’t like extended exposure in the water.” Iggy added before looking around. “Where did you steal this blond human from?”

“The lighthouse.” Gladio supplied easily as he brought Prompto in closer to hug him. “Relax we’ll be back in no time.” 

Despite the advice Prompto couldn’t relax. His brain was torn between being scared shitless and having the time of his life. He was hanging out with mer and how cool was that, but he was truly helpless and that was not a good thing. When the familiar rock outcropping near the beach came into view he nearly cried out in joy.

A small but fairly troublesome issue came to light once he was safely crawling towards dry land on the beach. His damn tail was still glued to his legs like a second skin. The three mer had followed him out of the water and the sight was a slightly unnerving. True to Gladio’s word they were all half human half octopus. Gladio was dark brown with massive tentacles and Iggy was purple with darker spots. Noct was midnight blue and almost looked metallic in the setting sun. All three had matching patterns on their upper bodies. The one advantage it seemed to having octopus legs was the ability to simulate walking, sort of. None of them did it gracefully but they were able to hobble around the small beach and explore. 

Wiggling further up the beach Prompto tried to tackle his own problems. Getting out of his fish tail was proving harder than expected. Fumbling with the zipper with shaking fingers he could barely budge it. Iggy finally noticed his struggles and waddled over. Prompto hadn’t seen in the water but the octoman all had webbed, clawed hands. 

Iggy tentatively reached out a purple speckled hand and pointed to his zipper. “May I assist you?”

“Its stuck!” Prompto managed. 

The mer was very patient and after a moment he managed to get the zipper moving and Prompto was finally free. The second his legs were out of the tail he collapsed on the sand and closed his eyes.

“Human! Can you build us a fire?”

Prompto popped his eyes open to see that Noct had come closer and asked. He’d already amassed a collection of beach glass in his eight legs. “Sure, um – I gotta catch my breath and then I can grab some firewood.”

“Can you cook us fish?” The mer asked with wide eyes. “We don’t get to eat cooked fish often.” 

“I don’t have any right now but uh if you come ba--,”

“I’ll go catch us one.” Noct blurted as he crawled towards the sea. “Gladio! Come here and hold my stuff.” 

The large octoman sighed and followed after Noct. They both disappeared and Prompto was left with Iggy on the beach. 

“This shall be fun, we’ve not had a fun outing like this in ages.” Iggy announced with a grin, highlighting his sharp teeth. “Do you require assistance gathering wood?”

Nodding vaguely they both began collecting wood. Given the circumstances Prompto was somewhat okay with how things were going. Soon enough Noct and Gladio returned with the best looking fish he’d seen in a long time. The fire was lit and the four of them sat around talking and eating. 

When Prompto had gone into the cottage earlier to grab a lighter he had brought back a blanket. He wasn’t cold blooded like the mer. He actually needed the fire and blanket to stay warm. It wasn’t until the moon was high in the night sky did he truly realize what an adventure he’d had. He’d been a mer for a split second. 

Finally the night had to come to an end and the three mer were making their way back to the sea. Gladio paused mid-way on the beach and turned to him. “Hey, so when are you going to wear your tail again?”

Unsure if he was ever going to risk doing it again Prompto struggled to think of a response. 

“We can teach you how to swim so you don’t sink.” Noct enthused as he waddled back over. “Iggy, can we come back tomorrow? I wanna collect more stuff.”

“Did you ask the human if he is free?” Iggy checked with a smirk. “We’ve not even been properly introduced.” 

“I asked his name earlier!” Noct huffed. “It’s Prompto.” Pausing for effect the dark haired mer puffed out his chest. “So Prompto, when are you free tomorrow?” 

**Author's Note:**

> Check me out on tumblr if you want. Just mostly FFXV stuff with some random dribbles. [BGN846 Blog](https://bgn846.tumblr.com/)
> 
> or Twitter [ BGN846 Twitter](https://twitter.com/BGN846?lang=en)
> 
> Please don't copy or plagiarize my work. Thanks! Disclaimer: I don’t own Final Fantasy XV or any of its contents.


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